According to Brookline police Sgt. Keith Hervieux, an investigation by Hollis police into who abandoned at least a dozen kittens — one was hit and killed by a passing vehicle — on Halloween night led them to believe Gay was the owner of the animals.

That investigation sent police to Gay’s former address on Old Milford Road in Brookline, which she had recently moved from. According to Hervieux, police approached the residence and detected a “strong odor of cat urine” coming from inside the home.

“The smell was awful,” Hervieux said Wednesday night.

Police were given access to the home by the current property owner, and a representative of the nonprofit animal shelter Kitty Angels of Tyngsborough, Mass., entered the dwelling.

“The home was in a real state of disrepair, with trash everywhere and a very strong odor of cat urine,” said Hervieux.

Inside, investigators found and rescued seven abandoned cats, all in poor health and suffering from flea infestations. Several were also later diagnosed with an intestinal infections, giardia and/or dermatitis, said Hervieux.

A 6-year-old male cat, dubbed Salem by rescue personnel, was found to have a bullet fragment in his abdomen, with missing teeth, one broken tooth and a torn eyelid. All of the cats were hospitalized for treatment of their conditions, Hervieux said.

Police believe Gay was also involved in an abandoned kitten incident on Halloween night in Hollis. In that case, police responded to a call from John Cordileone of Brookline just after midnight; he reported finding the kittens alongside a road.

Police determined the animals were intentionally abandoned; they worked with Cordileone to round up six of the young cats.

One was adopted by one of the responding police officers. Two others were adopted by a family in town. The remaining kittens were taken in by staff at Kitty Angels to be treated by a veterinarian.

Gay was released on $10,000 personal recognizance and ordered to be arraigned in the 9th Circuit Court-Milford on Feb. 20 at 8:30 a.m.